1. Field of the Invention
The present invention relates to watermarking material and to transferring watermarked material.
Material means one or more of image material, audio material and data material. Image material is generic to still and moving images and includes video, whether compressed or not.
This specification uses the terms “seller” and “buyer” in relation to such to material for convenience and ease of description. It will be appreciated that those terms do not simply mean someone (seller) who transfers outright ownership to someone else (buyer) for a consideration usually money. Often, material is licensed to a user (buyer) by a licensor (seller) who allows the licensee to use the material in accordance with defined terms or business rules. Thus the terms seller and buyer have more general meanings and include intermediaries acting on behalf of other persons who may be the ultimate owners of the material and the ultimate users thereof.
2. Description of the Prior Art
It is known to watermark material. Data may be embedded as a watermark in the material. A watermark may be imperceptible or perceptible in the material. The present invention uses perceptible watermarks and optionally may also use imperceptible watermarks.
A watermark may be used for various purposes. It is known to use watermarks for the purpose of protecting the material against, or trace, infringement of the intellectual property rights of the owner(s) of the material. For example a watermark may identify the owner of the material.
Watermarks may be “robust” in that they are difficult to remove from the material. Robust watermarks are useful to trace the provenance of material which is processed in some way either in an attempt to remove the mark or to effect legitimate processing such as video editing or compression for storage and/or transmission. The present invention uses robust watermarks. Watermarks may be “fragile” in that they are easily damaged by processing which is useful to detect attempts to remove the mark or process the material.
It is known to offer watermarked images for sale over the interne. Watermarked images may be downloaded for inspection and for examination for suitability for the users' desired purpose. If the user wishes to purchase an unwatermarked image, the user agrees to conditions of sale, for example an end user License, and pays for the image e.g. by credit card. The user is then able to download the unwatermarked image.